Pump



July 22 1924. 1,502,47Q

l. B. HART fulylP Filed Nbv. e 1920 s Sheets-Sheet. 1

I. B. HART PUMP Filed Nov. 6, 1920 5 Sheets-Sheet, 2

[NV TOR I. B. HART PUMP I Filed Nov. 6, 1920 3 Sheets-Sheet. 5

Patented duly 22, 1924.

IRA B. HART, OF ST. LOUIS, MISSOURI, ASSIGNOR, BY MESNE ASSIGNMENTS, TO ST.

LOUIS PUMP AND EQUIPMENT COMPANY, OF ST. LOUIS, MISSOURI, A CORPORA- TION O'F MISSOURI.

PUMP.

Application filed November 6, 1920. Serial No. 422,140.

T all whom it may concern:

Be it known that I, IRA B. HART, a citizen of the United States, and aresident of city of St. Louis, State of Missouri, have invented an Improvement in Pumps, of which the following is a specification.

This invention relates to mechanical apparatus, and with regard to certain more specific features, to a rotary pump for liquids.

Among the several objects of the invention may be noted the provision of simple and inexpensive apparatus for' pumping liquids; the provision of a durable and reliable structure adapted to withstand severe service conditions; and the provision of a self-lubricating construction in which the lubricant-supplying means require attention or renewal only at long intervals. Other objects will be in part obvious and in part pointed out hereinafter.

The invention accordingly consists of the elements and the combination of elements, features of construction, and arrangements of parts which will be exemplified in the structures hereinafter described and the scope of the application of which will be indicated in the following claims.

In the accompanying drawings in which are shown two of various possible embodiments of the invention.

Fig. 1 is a side elevation;

Fig. 2 is a transverse vertical'section on the line 22 of Fig. 1, showing in dotted lines a second position of the piston and the associated parts;

Fig. 8 is a longitudinal vertical section on the line 33 of Fig. 2;

Fig. 4 is a plan; Fig. 5 is a horizontal section on the line 55 of Fig. 2;

Fig. 6 is a fragmentary right side elevation, viewed from the line 6-6 of Fig. 1;

Fig. 7 is a horizontal section on the hue 7-7 of Fig. 2;

Fig. 8 is a section of a bushing shown in Fig. 3, on an enlarged scale; Fig. 9 is a side elevation, similar to Fig. 1, showing a modification; Fig. 10 is a transverse vertical section,

similar to Fig. 2, taken on the line 10'10 of Fig. 9;

Similar reference characters indicate corresponding parts throughout the several views of the drawings.

Referring now more particularly to Figs. 1 to 8, there is illustrated at 1 a cast-iron frame or casing or cylinder member having the two cylindrical compartments 2, 3 separated by a vertical partition 4. A horizontal steel shaft 5 runs lengthwise through the cylinder and is mounted in bronze bushings 6, 7 pressed into .recesses in the cast-iron cylinder heads 8, 9 that are bolted to either end of the cylinder 1.

The head 8 at one endthe left end in Fig. 3is blind, that is, the shaft does not extend through it. This eliminates leakageat this end of the pump and makes it uniecessary to provide any packing at this on At the other end, the head 9 has secured to it by bolts and nuts 12 a cast-iron gland 10 that holds in place the packing material 11. The bolts are tightened from time to time to keep the packing tight.

The gland 10 is separate'from the bushing 7. This insures improved results, because the gland is designed to act simply as a gland, and the bushing is designed to serve solely as a bushing. Furthermore, the bush- 'ing has a constant surface in contact with the shaft and in contact with the element (cylinder head) that supports the bushing,-a feature that is not found in this simple form in many constructions where the bushing acts as a gland.

The bushings 6, 7 have grooves such as the grooves 13 (Fig. 8) on their inner surfaces, and these grooves are filled with a fairly permanent lubricating medium such as is indicated at 14 in Fig. 8. The lubris cant is preferably graphite or a graphite composition, with a suitable binder. When the pump is new this lubricant is flush with v the inner surface of the bushings, and effectively lubricates the shaft, preventing the frictional heat that must be guarded against in pumps handling gasoline and similar liquids. After the pump has been in use some time, the surfaces of bushings and shaft acquire a glazed finish that reduces the friction to such a point that as the lubri-.

cant wears away there is less of it needed, making it unnecessary to renew the bushing s except at longintervals. Lubricat on of the bearings between frame and shaft is thus automatic and self-contained.

In order to reduce further the frictional heat at the packing 11, the shaft 5 has sweated upon its reduced portion 15 a brass sleeve 16. This construction makes possible the desirable dissimilar metals combination (brass and cast-brass) between shaft and gland, and at the same time makes possible the desirable dissimilar metals combination (steel and bronze) between shaft and bushing, as well as the compactness and economy of having the shaft constructed of steel rather than of some other material such as brass. The advantage of the present construction, moreover, would not be as fully attained if the bushing and gland were a single piece.

The shaft 5 is driven from any suitable motor (not shown) and has fixed to it two steel eccentrics 17, one in each of the two compartments. These eccentrics are spaced oppositely to each other, that is, 180 degrees apart, in order that the rotating parts of the pump may be balanced. Each eccentric is fixed to the shaft with a drive fit and is held in place by keys 18. The sides of the eccentrics cooperate with the adjacent walls of the partition 4 and cylinder heads 8, 9 to act as end-thrust bearings. If there is any undue end-thrust, the fact that the eccentrics are of steel and the cylinder heads and partition of cast-iron is of advantage in this connection, as this com bination of dissimilar metals reduces the friction between the parts. Preferably there is a small clearance between these surfaces (a liquid seal forming there and preventing leakage), and in ordinary running there is seldom if ever any material contactbetween these parts.

Each eccentric carries a bronze ringshaped piston. The piston does not rotate with the eccentric, but has a peculiar oscillating movement due to its pivotal connection 20 with a rocker-arm 21 which in turn is pivoted upon the pin 22 fixed in bosses 23 in the cylinder member 1. In assembling the pump the pin 22 is slid through the perforations in the bosses 23 and rockerarm 21 and is preferably a little shorter than the length of the cylinder, so that there is a clearance between the pin and the cylin der heads when the latter are secured in place.

The depth or radial thickness of the piston 19 is equal to the radial distance between the cylinder and the outermost point of the eccentric, minus a slight clearance, so that as the shaft and the eccentric rotate. for example in a counter-clockwise direction (Fig. 2), the outer surface of the piston travels along the entire inner surface of the cylinder but normally never quite touches it. The intervening space is small .neoaavo enough so that it is bridged by a line or film of the liquid forming what may be called in this instance a counter-clockwise traveling line-seal 2-1 (Fig. 2) between piston and cylinder.

This traveling movement squeezes or forces toward and into the discharge port and line 25 all of the liquid that is in the decreasing space ahead of the traveling lineseal 24 and at the same time draws liquid from the intake line and port 26 into the increasing space behind the traveling lineseal.

The pumping action lasts from about the time the traveling line-seal passes the point 27 until about the time it reaches the point 28. This means that pumping is done during almost the entire movement of the shaft, eccentric and piston.

During the small remaining part of the travel of the line-seal, that is, from about the point 28 to about point 27, the seal is broken as the piston passes the discharge and inlet ports. To prevent liquid from backing through the pump at this time, the piston is provided with a pivoted steel blade or check 29 (Fig. 2). During the working part of the stroke this check lies against the piston, which is. countersunk to permit it to do so. When the liquid tends to back through the pump, the liquid enters the space between the piston and the under side of the check, one or both parts being cut away as at 30 to facilitate this action. The check then remains in contact with the cylin; der wall until the traveling line-seal reaches about the point 27 again in its counter-clockwise travel, the seal is formed again, and the next working stroke begins.

The piston is connected to the rocker-arm by a steel boss or piston-support 31 mounted on a tie-block 32 that is seated in a recess in the piston. Bolts 33 pass through the piston-support and the tie-block and are threaded into the piston. As shown in Fig. 2, the piston-support 31 fits in a. recess in the rocker-arm. The latter is of bronze. The dissimilar metals combination (bronze and steel) between rocker-arm and pistonsupport is of advantage, in that it reduces the friction at the points where these surfaces are in contact. The same dissimilar metals combination also reduces friction at the points where the rocker-arm is in contact with its steel supporting-pin 22.

Lubrication between piston and eccentric is of the same type as between bushings and shaft, as described above. The bronze piston has grooves 13 on its inner surface, and thesegrooves are filled with a fairly permanent lubricant 14 that keeps the frictional heat down to a negligible amount. When the pump is new and before the engaging surfaces of piston and eccentric have become glazed the lubricant is flush with the inner surface of the piston and supplies itself freely. Later, before the lubricant has worn away materially, the surfaces have acquired a glazed finish so that less of the lubricant is needed. The lubricant thus lasts a long time, and lubrication between piston and cocentric is thus automatic and self-contained.

The sides of the pistons have normally a clearance from the adjacent Walls of the partition and the cylinder heads. When there is any contact between these parts, however, any frictionalvheat developed thereby is reduced, by the fact that the piston is of bronze and the adjacent walls of cast-iron.

In the construction shown in Figs. 1 to 8 the cylinder casting extends upwardly to form a by.-pass chamber 34 connected by apertures 35 in the wall 36, to the intake port 26. The by-pass or relief valve 37 is a poppetvalve having a stem 38 slidably mounted in a valve guide 39 screwed onto the top of the cylinder member. A compression spring 40 surrounds guide and stem, forcing the valve downwardly against its 1 brass seat 41. A gasket 42 is provided at the junction of guide and cylinder member, for packing purposes.

The discharge is around the rocker-arms 21. The spring holds the valve against its seat to withstand a predetermined pressure, such as fifty pounds to the square inch. When this pressure is exceeded the relief valve opens and allows the liquid in the discharge line 25 to pass through the by-pass chamber 34 and apertures 35 to the intake line 26.

In the modification illustrated in Figs. 9 and 10 the by-pass feature is omitted.

From the above it will be seen that the several objects of the invention are realized, and other advantageous results attained.

As various possible embodiments might be made of the above inventions and various changesmight be made in the embodiments above set forth it is to be understood that all matter herein set forth or shown in the accompanying drawings is to-be interpreted as illustrative and not in a limiting sense.

I claim:

1. In apparatus of the class described, in combination, a cylinder member having a plurality of compartments; a steel shaft therethrough; each compartment having in it an eccentric fixed upon and rotatable with the shaft, a piston rotatably mounted upon the eccentric bosses upon the cylinder member, a pin mounted therein, a bronze rockerarm pivotally mounted on said pin a tieblock upon the piston, a steel boss or piston support on said tie-block and bolts securing said piston-support and tie-block upon the piston, the piston-support fitting'in a recess in the rocker-arm to form a pivotal connect1on between piston and rocker-arm."

having 2. In apparatus of the class described, in

combination, a cylinder member having a plurality of compartments; a steel shaft therethrough; each compartment having in it an eccentric fixed upon and rotatable with the shaft, a piston rotatably mounted upon the eccentric, bosses upon the cylinder member, a pin mounted therein, a bronze rockerarm pivotally mounted on said pin a tieblock upon the piston, a steel boss or pistonsupport on said tie-block, and bolts securing said piston-support and tie-block upon the piston, the piston-support fitting in a recess in the rocker-arm to form a pivotal connection between piston and rocker-arm; and bushings with lubricating material inset therein, for mounting the shaft and lubricating it, the pin being mounted, independently of said heads.

3. In apparatus of the class described, in combination, a cylinder member having a plurality of compartments; 2. steel shaft therethrough; each compartment having in it a steel eccentric fixed upon and rotatable with the shaft, a bronze piston rotatably mounted upon the eccentric and adapted to form a traveling line-seal with the cylinder, bosses upon the cylinder member, a pin mounted therein, a bronze rocker-arm pivotally mounted on said pin, a tie-block upon the piston, a steel boss or piston-support on said tie-block, bolts securing said pistonsupport and tie-block upon the piston, the piston-support fitting in a recess in the rocker-arm to form a pivotal connection between piston and rocker-arm, and check pivoted upon the piston and adapted to swing against the adjacent cylinder wall to prevent back-flow of fluid; heads secured to either end of the cylinder member and having bronze bushings with lubricating material inset therein, for mounting the shaft and lubricating it.

4. In apparatus of the class described, in combination, a cylinder member having a plurality of compartments; a steel shaft therethrough; each compartment having in it a steel eccentric fixed upon and rotatable with the shaft, a bronze piston rotatablymounted upon the eccentric and adapted to form a traveling line-seal with the cylinder, bosses upon the cylinder member, a pin mounted therein, a bronze rocker-arm pivotally mounted on said pin, a tie-block upon the piston, a steel boss or piston-support on said tie-block, bolts securing said pistonsupport and tie-block upon the piston, the piston-support fitting in a reccess in the rocker-arm to form a pivotal connection between piston and rocker-arm, and a check pivoted upon the piston and adapted to swing against the adjacent cylinder wall to prevent back-flow of fluid; heads secured to either end of the cylinder member and bronze bushings with lubricating materlal inset therein, for mounting the shaft and lubricating it; each piston having such lubricating material in its surface adjacent the eccentric, to lubricate the bearings between said parts; one head only being perforated to permit the shaft to pass therethrough.

5. In apparatus of the character described, a cylinder member having a plurality of compartments, a steel shaft therethrough, a plurality of steel eccentrics fixed upon and rotatable With the shaft, a bronze piston mounted upon the eccentric and adapted to oscillate upon the rotation thereof, bosses upon the cylinder member, a pin mounted therein, a bronze rocker arm pivotally mounted in said pin, a tie block upon the piston, a steel boss or piston support on said tie block, bolts securing said piston support and tie block upon the piston, the piston support forming a pivotal connection between piston and rocker arm, and a check pivoted upon the piston to prevent back flow of fluid; heads secured to either end of the cylinder member and having bronze bushings With lubricating material inset therein for mounting the shaft and lubricating it; said pistons having such lubricat ing material in its surface adjacent the eccentric to lubricate the bearings between the shaft.

In testimony whereof, I have signed my name to this specification this 4 day of November, 1920.

IRA B. HART. 

